Document size conversion circuit for a document filing system

Abstract

Picture information stored in a memory device is read out and written into a page buffer and visually displayed on the screen of a CRT display under control of an interface unit for display, through a size conversion circuit.

What is claimed is: 
     
       1. A document size conversion circuit for a document filing system comprising: an information input terminal to which pieces of line picture information are supplied;   a plurality of memories each adapted to store one of said pieces of line picture information supplied to the terminal;   means for forming a matrix array of local picture information consisting of bits extracted from said plurality of memories;   means for obtaining a picture dot position in said matrix array of local picture information, the picture dot position corresponding to a size conversion rate;   means for obtaining an average gray level of said matrix array of local picture information with respect to said picture dot position; and   comparator means for comparing said average gray level and a predetermined slice level to form size converted data.   
     
     
       2. A document size conversion circuit according to claim 1, wherein said picture dot position obtaining means includes: conversion rate setting data supplying means; and   X-direction and Y-direction distance calculating means for calculating an address designating signal from said size conversion rate setting data.   
     
     
       3. A document size conversion circuit according to claim 2, wherein said average gray level obtaining means includes arithmetic memory means for storing a plurality of average gray level data by using said address designating signal. 
     
     
       4. A document size conversion circuit according to claim 1, wherein said matrix array of local picture information forming means includes a plurality of latches for latching said bits extracted from said memories.